Resumen

Let K be a field of characteristic O, and let R denote K[X] or K[[X]]. It is well known that the roots of a polynomial FisinR[Z] are fractional powers series in K[[X 1d/]], where Kmacr is a finite extension of K and disin N, and they can be obtained by applying the Newton Puiseux algorithm. Although this is not true for polynomials in more than one variable, there is an important class of polynomials FisinR[Z] (R=K[[X 1, . . ., X n]]=K[[Xlowbar]]), called quasi-ordinary (QO) polynomials, for which the same property holds (i.e. their roots are fractional power series in Kmacr[[Xlowbar 1d/]]). The goal of the paper is to give an algorithm to compute these fractional power series for K (a computable field) and n=2